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Tons of concrete, massive bolts to secure windmill to earth

PORTSMOUTH —The wind turbine itself won't arrive at Portsmouth Abbey School until March, but last week its anchor was set. No ordinary anchor, this one should have extraordinary holding power, according to the Abbey's Brother Joseph Byron.

"That turbine isn't going anywhere," he said Thursday. "I think the earth would have to tip over" for it to tumble.

The ingredients for that base rolled into the school aboard caravans of trucks. Twenty mixer trucks full of cement and eighty 27-foot long by one-inch diameter steel rods all sunk through bedrock in a 30-foot deep hole should keep the turbine firmly tethered to earth.

It has been quite a process, Brother Joseph said.

The template that served as a guide for those bolts arrived last fall. Signaling the start of actual work, it was greeted with excitement, Brother Joseph said.

Until it was discovered that it was the wrong template, meant instead for a similar turbine to be built at the Mass. Maritime Academy. A new one had to be fabricated in a hurry in Texas and arrived only recently.

Next, a hole had to be dug — 30 feet deep by 15 feet across. Halfway down they struck rock, "solid rock all the rest of the way down."

The school located a licensed blasting company which agreed to take on the job.

Before the charges were set, Brother Joseph had a few questions.
How high will the explosion go," he asked.

"We just don't know," was the reply.

Will it rattle the buildings nearby?

"We just... more [truncated due to possible copyright]  
"That turbine isn't going anywhere," he said Thursday. "I think the earth would have to tip over" for it to tumble.

The ingredients for that base rolled into the school aboard caravans of trucks. Twenty mixer trucks full of cement and eighty 27-foot long by one-inch diameter steel rods all sunk through bedrock in a 30-foot deep hole should keep the turbine firmly tethered to earth.

It has been quite a process, Brother Joseph said.

The template that served as a guide for those bolts arrived last fall. Signaling the start of actual work, it was greeted with excitement, Brother Joseph said.

Until it was discovered that it was the wrong template, meant instead for a similar turbine to be built at the Mass. Maritime Academy. A new one had to be fabricated in a hurry in Texas and arrived only recently.

Next, a hole had to be dug — 30 feet deep by 15 feet across. Halfway down they struck rock, "solid rock all the rest of the way down."

The school located a licensed blasting company which agreed to take on the job.

Before the charges were set, Brother Joseph had a few questions.
How high will the explosion go," he asked.

"We just don't know," was the reply.

Will it rattle the buildings nearby?

"We just don't know." Fact is, we have never done a round hole before, but we found a book and are confident that we know how to do it.

With faculty and student spectators gathered at a safe distance, the charge was exploded.

"A mound rose up about 15 feet with a big, dull boom, then it settled back into the ground," Brother Joseph said.

The demolition team, it turned out, did know its business. The hole in the shale bedrock was indeed round and exactly the prescribed dimensions.

Next, a 15-foot diameter corrugated steel pipe, of the sort used in drainage systems, was lowered into the hole and an outer two-foot ring of cement (120 cubic yards worth) was poured between the pipe and the bedrock to form an outer shell.

A team of laborers, among them Brother Joseph, Paul Jestings, the school's director of operations, and Henry duPont, ("Our wind turbine expert from Block Island") climbed down into the hole and threaded the 80 heavy threaded rods into their templates. It is to these rods that the turbine tower will be bolted.

Another corrugated pipe, this one narrower at 13-feet, was lowered into the hole and filled to the top with dirt. Then the two-foot space between the two pipes was filled with 80 yards of concrete, effectively sandwiching the bolts in solid concrete. The whole thing was capped with reinforced concrete and, once cured, will provide an immovable foundation for the turbine to come.

Before the turbine parts can be shipped in March, a company 'scout' will visit to determine a route. Since the tower is too heavy for the Sakonnet River Bridge, it will probably have to come by way of the Newport Bridge. And Brother Joseph said he hopes the turn from Cory's Lane into the hockey rink parking lot isn't too tight for the long load.

Recently, the Abbey received the permit it needs from the Federal Aviation Administration (FAA). A flashing red light will sit atop the tower warning low-flying aircraft away.

"It has been a ton of work but things are coming together," he said. They have been "blessed" by mild winter weather, as well as some student family connections — one student's father owns a construction company (he agreed to pitch in). And the owner of an excavating firm was recruited to dig the hole while on the sidelines watching his grandson play football.

Portsmouth Abbey earned its approvals for the $1.25-million project in April, when the town's zoning board of review unanimously decided to issue the school a special use permit and a height variance for the 164-foot structure.

The school expects the turbine to supply nearly half of the school's 2-million kWh use throughout its 500-acre campus.

Source: http://www.eastbayri.com/st...

FEB 4 2006
https://www.windaction.org/posts/1175-tons-of-concrete-massive-bolts-to-secure-windmill-to-earth
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